A conventional connection device for connecting a bag to the carriage rack of a bicycle generally includes a base which is connected to the carriage rack and the bag is connected to the base at its bottom. Two fixed hooks extend from a side of the base and a movable hook is connected on the other side of the base. The fixed hooks and the movable hook are respectively hooked with the carriage rack and the bottom of the bag. Two support hooks are connected to a side of the movable hook and cooperated with two fixed hooks so as to perform the support legs of the bag. The base includes drain holes such that rain drops are not trapped in recessed areas of the base. The conventional connection device is designed to connect small bag to the bicycle and the bag is designed to be position on the top of the carriage rack.
A conventional connection device for connecting a bag to a side of the bicycle and there are two fixed hooks on the base of the bag so as to hook to the side of the carriage rack. A movable hook is slidably connected to the lower end of the base and hooked to a support rod of the carriage rack. However, the positions of the fixed hooks are not adjustable and might not be suitable for some carriage rack. The fixed hooks and the movable hook protrude from the back board of the bag so that the bag cannot be used as a backpack.
The present invention intends to provide a connection device for connecting a bag to a side of a bicycle carriage rack and the bag has a smooth back and can be used as a backpack.